Operating means for lifting-jacks.



J. B. SMYTHB.

OPERATING mmns FOR LIFTING JAOKS.

APPLICATION FILED 111N323, 1913.

1,096,401 Patented May 12, 1914.

2 SHEETS-SHEET 1. E91.

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OPERATING MEANS FOR LIFTING JAcKs.

APPLICATION FILED JUNE 23, 1913.

Patented May 12, 1914,

2 SHEETS-SHEET 2.

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' ED STATES PATENT OFIG JOSEPH IB. SMYTI'IE, 0F GOATICOOK, QUEBEC, CANADA.

OPERATING MEANS FOR LIFTING-J'ACKS.

Specification of Letters Patent.

Original application filed October 26, 1912, Serial No. 728,262. Divided and this application filed June 23,

Serial N0. 775,429.

To all whom it may concern Be it known that I, J osnrn B. SMYTHE, a subject of the King of England, and a resident of Coaticook, Province of Quebec, Ganada, have invented certain new and useful Improvements in Operating Means for Lifting-Jacks, of which the following is a speci fication.

This invention relates to operating means for lifting jacks and particularly to that form of jacks which are known as ratchet screw jacks, and has for its object the provision of means whereby the lowering of the movable member may be controlled manually.

The invention consists in providing the jack with a ratchet adapted to be rotated by the reverse movement of the devices for rais ing the movable member and controlling this rotation of said ratchet by means of two pawls alternately adapted to engage the teeth of the ratchet, thereby permitting said ratchet to rotate intermittently.

This application is a division of application of the same inventor for U. S. patent for lifting jacks, filed October 26, 1912, Ser. No. 728,262.

The invention further consists of an oscillating member for imparting movement to said pawls and a crank for operating said oscillating member.

The invention further consists in certain novel features of construction and arrangement of parts which will be readily understood by reference to the description of the drawings and to the claims hereinafter given.

Of the drawings: Figure 1 represents a vertical section of a jack embodying the features of the present invention. Fig. 2 rep resents a vertical section of a portion of the same, showing the devices for controlling the lowering of the movable member. Flg. 3 represents an elevation of the upper portion of the jack, and Fig. 4 represents an elevation of the devices for controlling the lowering of the movable member.

Similar characters designate like parts throughout'the several figures of the drawin s.

In the drawings, 10 represents a suitable base supporting a stationary standard 11, over the outer periphery of which is fitted a movable sleeve 12 to the up er end of which is threaded a cap 13. In t e upper end of the standard 11 is mounted a nut 14: to wh ch is threaded a lifting screw 15 having spllned to its upper reduced end a gear 16 wlth which meshes the gear 17 formed upon or secured to a revoluble shaft 18. The outer end 1s provided with a suitable operating p eehanism 1t) of any wellknown construcion.

Interposed between the upper face of the gear '16 and the wall of the cap 13 are two annular plates 20 and 21 between which are interposed a plurality of anti-friction members 22. On the spindle 18 and secured thereto is a ratchet wheel 23, which is surrounded by a gear 2 1 having mounted therein the pawls 25 adapted to engage the teeth of the ratchet wheel 23 when the movable member 12 is lowered and move said ratchet wheel in the direction of the arrow a on Fig. 4: of the drawings. This gear 241 meshes with the pinion 26 having a spindle 27 extending through the closing plate 28 secured by means of the screws 29 to the flanges 30 formed upon the movable member 12. Keyed to the spindle 27 and revoluble therewith is a ratchet wheel 31 adapted to move in the direction of the arrow 6 on Fig. 1 of the drawings when the movable member 12 is lowered. The closing plate 28 has extending therethrough the spindle 32 of an oscillating member 33, said spindle being intermediate the ends of said member 33, the outer ends of which are forked and. have pivoted thereto at 341 and 35 the pawl members 36 and 37. The outer pawl member 36 is normally in engagement with one of the teeth of the ratchet 31, thereby preventing its movement in the direction of the arrow 1), thus resisting any tendency of the movable member 12 to lower under its load.

Secured to the outer end of the spindle 32 is a lever 38 provided with a slot 39 therein extending lengthwise thereof. In the slot 39 is positioned the cylindrical stud 4-0 formed upon or secured to a crank arm 11 provided with a spindle l2 extending through a bearing in the closing plate 28 in which it is free to revolve. The outer end 13 of the stud 10 is squared and adapted to receive the handle 1 1. When it is desired to lower the movable mcmber 12 under its load the operator by means of the handle 4d may turn the crank 11 about the axis of its spindle i2, thereby producing through the medium of the slotted lever 38 an oscillation of the member 33. As this member 33 oscillates and the pivot pin 34: moves upwardly it will permit the extreme end of the pawl 36 to ride over one of the teeth of the ratchet wheel 31, the downward movement of the pawl 37 during the oscillation of the member 33 tending to force said pawl 36 outwardly from the path of the teeth of sald ratchet wheel 31. As the pawl 37 moves downwardly it will clear the point of one of the teeth of the ratchet wheel 31 and then be forced inwardly, by means of the cam portion 45 on the pawl 36, into the path of the next tooth, thereby retarding the movement of the ratchet 31 until a complete oscil lation of the member 33 has been completed and the extreme lower end of the pawl 36 has passed over one tooth into position to engage the next. The plate 28 is provided with a lug 46 which limits the outward movement of the pawl 36, which pawl is provided with a cam surface 17 at its extreme upper end coacting with the fixed pin or stud 48 to regulate the movement of the said pawl 36 during the oscillation of the member 33. The upper end of the pawl 36 is provided with a spring 49 which tends to keep the cam surface 47 in contact with the periphery of said pin 18. The upper end of the pawl 37 is also provided with a spring 50 engaging a fixed stud or pin 51. In the normal position with a load on the jack both pawls 36 and 37 are in engagement with the teeth of the ratchet 31 and when they are oscillated the pawl moving downwardly takes the load off the upwardly moving pawl, which is then thrown out by the spring on its upper end. The lnner or short pawl 37 is not in contact with the inner side of the pawl 36 excepting when free from lead and on its downward movement. It is obvious that when the crank 11 is in the position indicated in Fig. 3 of the drawings, the pawls 36 and 37 are retained in the position shown in Fig. 1 of the drawings, said pawl 36 thereby preventing any movement of the ratchet wheel 31 in the direction of the arrow 6 and consequently pre venting the lowering of the movable member 12. When a load is placed upon the jack the tendency of the ratchet 31 to move in the direction of the arrow 5 will cause the pawl 36 to move upwardly a slight distance and force the pawl 37 inwardly into engagement with a tooth of said wheel 31. As soon, however, as it is desired to lower the said movable member 12, the operator may, by means of the handle 44, rotate the crank 41, and by oscillating the member 33 secure an intermittent rotation of the ratchet wheel 31 and consequently the gears 24, thereby permitting the slow lowering of the movable member. In this operation the downward movement of either pawl 36-37 will revolve the ratchet Wheel 31 slidably backward to relieve the load on the other pawl which will then be thrown from engagement with the ratchet tooth by the spring on its upper end.

The lowering of the movable member may be regulated to any desired speed by varying the speed of rotation of the handle M. This makes a very effective means for controlling the lowering of the jack, and is very positive in its operation.

It is believed that the operation and many advantages of this invention will be fully understood from the foregoing description.

Having thus described my invention, 1 claim:

1. In a device of the class described, the combination of a ratchet wheel freely revoluble in one direction; an oscillating member; pawls secured to the ends of said oscillating member normally engaging said ratchet to prevent movement thereof in the opposite direction and adapted to be disengaged alternately from the teeth of said ratchet wheel to permit an intermittent reverse rotation thereof; a spindle secured to said oscillating member; an operating member secured to said spindle provided with a longitudinal. slot; and a revoluble crank provided with a lug engaging said slot to impart an oscillating movement to said operating member.

2. In a device of the class described, the combination of a ratchet wheel freely revoluble in one direction and adapted to be rotated in a reverse direction; an oscillating member; pawls secured to the ends of said oscillating member normally engaging the teeth of said wheel and adapted to be disengaged alternately therefrom to permit an intermittent reverse rotation thereof; a spindle secured to said oscillating member; an operating member secured to said spindle provided with a longitudinal slot; a revoluble crank provided with a lug engaging said slot to impart an oscillating movement to said operating member; and a detachable handle adapted to be attached to said lug and operate said crank.

3. In a device of the class described, the

combination of a ratchet wheel freely revo-- luble in one direction and adapted to be rotated in a reverse direction; a member adapted to be oscillated about a pivot intermediate its ends; pawls pivoted to the ends thereof adapted to be disengaged alternately from the teeth of said ratchet wheel; a fixed stud; and a yielding member secured to the inner pawl and adapted to bear against said stud to retain said inner pawl normally in engagement with the outer pawl.

1. In a device of the class described, the combination of a ratchet wheel freely revoluble in one direction and adapted to be rotated in a reverse direction; a member adapted to be oscillated about a pivot intermediate its ends; and a pawl pivoted to each end thereof, one of said pawls being provided with a cam surface adapted to engage the other pawl and force the latter into engagement with a tooth of said ratchet wheel when the first mentioned pawl is withdrawn from engagement with another tooth of said ratchet wheel.

5. In a device of the class described, the combination of a ratchet wheel freely revoluble in one direction and adapted to be rotated in a reverse direction; a member adapted to be oscillated about a pivot intermediate its ends; two pawls of different lengths pivoted to the ends thereof, the longer pawl being provided with a cam surface adapted to engage the shorter pawl and force the latter into engagement with a tooth of said ratchet wheel when the longer pawl is withdrawn from engagement with another tooth of said ratchet wheel; and means for retaining the opposed faces adjacent to the operating ends of said pawls in engagement with each other during the downward movement of the shorter pawl.

(3. In a device of the class described, the combination of a ratchet wheel freely revoluble in one direction and adapted to be rotated in a reverse direction; a member adapted to be oscillated about a pivot intermediate its ends; two pawls of different lengths pivoted to the ends thereof, the longer pawl being provided with a cam surface adapted to engage the shorter pawl and force it into engagement with a tooth of said ratchet wheel when the longer pawl is withdrawn from engagement with another tooth of said ratchet wheel; and a spring for retaining the opposed faces adjacent to the operating ends of said pawls in engagement with each other during the downward movement of the shorter pawl.

7. In a device of the class described, the combination of a ratchet wheel freely revoluble in one direction and adapted to be rotated in a reverse direction; a member adapted to be oscillated about a pivot intermediate its ends; two pawls of different lengths pivoted to the ends thereof, the longer pawl being provided with a cam surface adapted to engage the shorter pawl and force it into engagement with a tooth of said ratchet wheel when the longer pawl is withdrawn from engagement with another tooth of said ratchet wheel; means for retaining the opposed faces adjacent to the operating ends of said pawls in engagement with each other during the downward movement of the shorter pawl; and means for restricting the movement of the outer pawl to a predetermined path.

8. In a device of the class described, the combination of a ratchet wheel freely revoluble in one direction andndapted to be rotated in a reverse direction; a member adapted to be oscillated about a pivot inter mediate its ends; two pawls of different lengths pivoted to the ends thereof, the longer pawl being provided with a cam surface adapted to engage the shorter pawl and force it into engagement with a tooth of said ratchet wheel when the longer pawl is withdrawn from engagement with another tooth of said ratchet wheel; means for retaining the opposed faces adjacent to the operating ends of said pawls in engagement with each other during the downward movement of the shorter pawl; and fixed stops for restricting the movement of the outer pawl to a predetermined path.

9. In a device of the class described, the combination of a ratchet wheel freely revoluble in one direction; a member adapted to be oscillated about a pivot intermediate its ends; two pawls pivoted to said member and adapted to alternately engage said ratchet wheel; a slotted oscillating lever for controlling the alternate engagement of said pawls and movable with said oscillating member; and. a revoluble crank provided with a member coacting with the slot in said lever whereby during the rotation of said crank said lever and member will be oscillated and permit said ratchet wheel to be moved intermittently in the opposite direction.

Signed by me at Coaticook, P. Q, this 14th day of June 1913.

JOSEPH B. SMYTI'IE.

\Vitnesses CARL LYMAN, CAMILLE E. I)ESJARLA1S.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

